This invention belongs to the field of solenoids and equipment employing same such as tape transport mechanisms.
A tape transport mechanism is one example where, conventionally, a rather large solenoid has been required to move a pressure roller to hold a tape against a rotating capstan in play mode. As long as the machine is running, the pressure roller must be held in this position. Typically, it will require 24 Watts of electric power to pull the pressure roller to play position, and will require the same continuous power input to the solenoid to hold it in play position. This is wasteful of power, and generates heat.